It's easily over a million users world wide, and if it's not...it should be!
I have to tell you though, there really is one user that stands out above them all. My Wife. That's right, my wife is also a user, and even though she would never tell you....she enjoys linux. She is not my favorite user simply because she's an amazingly wonderful woman, but also because she's genuinely a fan of linux at this point. She uses it everyday at home and even on her laptop.
I remember that I mentioned to her that I wanted to get her a netbook with a built-in webcam so that she could use that to call me at home on my webcam. I was planning on getting a netbook for her with Windows XP installed on it (the program that we use with the webcam is for Windows or Mac only) and then I could answer the call in my Virtual Machine running Windows 7 beta. Here's a small part of the conversation we had:
How awesome is that! She actually asked for linux to be installed on her future netbook. I have to tell you, that makes me very happy. My wife is amazing.
Me: So we'll get you that netbook.
Me: Then we'll run the Z-PC100 in that.
Wife: Can you install Ubuntu on it?
Me: Really? You...want...Ubuntu on it?
Wife: Well, yea.
Wife: I've gotten so used to it that I don't want Windows on it.